1. Field of the Invention
The present invention relates to a lens apparatus, and more particularly, to a lens apparatus including a movable optical member and an electric operation unit for electrically driving the movable optical member, and to an image pickup apparatus including the lens apparatus.
2. Description of the Related Art
A small-sized lens apparatus, which is mounted onto a television camera or the like in a replaceable manner, generally includes a focus ring, a zoom ring, and an iris ring. A user (camera operator) rotates and operates those operation rings, to thereby adjust a focus position, a zoom magnification, an iris value, and the like. Modes of operating a lens include a case where the user himself/herself rotates and operates the operation rings while gripping the operation rings directly by hand (manual operation mode), and a case where an electric operation unit provided integrally with the lens is driven to rotate the operation rings (electric operation mode). The above-mentioned electric operation unit includes driving motors each connected to one of the operation rings through a gear. Through operation of various switches provided outside the electric operation unit, or in response to a control signal transmitted from a camera, the driving motors are driven by a predetermined amount to rotate the operation rings.
In order to deal with the above-mentioned different image pickup modes, there is disclosed a lens apparatus in which a mechanism for switching the operation mode between manual operation mode and electric operation mode is provided in the electric operation unit.
Japanese Patent No. 2,773,230 discloses the following lens apparatus. Specifically, in the lens apparatus, a clutch mechanism is provided in the electric operation unit. The clutch mechanism is switched to change the operation mode, for zooming and focusing, between the manual operation mode and the electric operation mode performed through motor driving. With this, the lens apparatus can deal with different image pickup modes.
In recent years, the above-mentioned lens apparatus including the electric operation unit has been becoming widely used as a cinematography lens. In cinematography, focusing and fine adjustment of a zoom magnification may be sometimes performed as visual effects during the image pickup operation, and hence each operation ring is required to be manually operated with high accuracy. Accordingly, there is known such an image pickup mode that the operation ring has mounted thereonto an external rotation operation accessory capable of rotating and stopping the operation ring with finer feeding accuracy than feeding accuracy when the user rotates the operation ring while gripping the operation ring directly by hand.
However, in the related art disclosed in Japanese Patent No. 2,773,230, when the external rotation operation accessory is mounted onto the operation ring, the rotation operation accessory is arranged at a position close to another operation ring. Thus, operability of another operation ring may be deteriorated. In order to ensure operability, it is necessary to arrange the external rotation operation accessory and another operation ring at a distance from each other. However, in a case where an interval between respective operation rings is increased, a distance between connection positions, at which the respective operation rings and the electric operation unit are connected together, is increased at the same time, with the result that the electric operation unit is upsized. Further, in a case where a width of a gear of each operation ring is increased to enlarge a distance in connection position between the electric operation unit and the external rotation operation accessory, a range of processing the gear is increased, which may lead to a problem of cost increase. Further, the gear of the operation ring is shared by the electric operation unit and the external rotation operation accessory, and hence the electric operation unit and the external rotation operation accessory need to have the same gear specifications (module). As a result, there is a problem in that the related-art lens apparatus is not applicable to the rotation operation accessories having specifications different from those of the electric operation unit.